NASA Orion: Interim Cryogenic Propulsion Stage (ICPS)

Artist concept of the NASA Orion spacecraft. 

The ICPS will boost the Orion to the correct altitude and trajectory needed to send the spacecraft around the moon in order to check out vital systems during the initial test flights. 

Image courtesy NASA. 

Some elements of a rocket can be familiar, like the boosters and engines, but there are several important parts on NASA's new rocket, the Space Launch System (SLS), that may be less widely known. The interim cryogenic propulsion stage (ICPS) pdf.

If the SLS was dissected, the ICPS lies just below the Orion capsule, at the top of the SLS.

The ICPS is a liquid oxygen/liquid hydrogen-based system.

On the first test mission of Orion and SLS together, called Exploration Mission-1, the ICPS will give Orion the big push needed to fly beyond the moon before the spacecraft returns to Earth.

For later long-duration missions in deep space, this interim stage will be replaced with a more powerful upper stage on SLS needed to carry crews and their spacecraft farther than ever before, including to an asteroid and ultimately Mars.

Orion will serve as the exploration vehicle that will carry the crew to space, provide emergency abort capability, sustain the crew during the space travel, and provide safe re-entry from deep space return velocities.

For the ICPS, The Boeing Co. will modify its existing Delta Cryogenic Second Stage (DCSS), used on United Launch Alliance's Delta IV family of launch vehicles.

It will be powered by an Aerojet Rocketdyne RL-10B2 engine, also currently used on the Delta Cryogenic Second Stage.

"Boeing's Delta Cryogenic Second Stage will need relatively minor modifications to be fully compliant with SLS requirements, which will keep us on schedule for the first two flights," said Chris Calfee, ICPS project manager at NASA's Marshall Space Flight Center in Huntsville, Alabama. Marshall manages the SLS Program for the agency.

Those modifications include lengthening the liquid hydrogen tank, adding hydrazine bottles for attitude control and making some minor avionics changes to meet the design parameters and performance characteristics as needed by NASA to meet the flight objectives.

"Affordability is key when a rocket as big and powerful as the SLS is needed for sustainable deep space exploration," said Steve Creech, assistant SLS Program manager for strategy and partnerships at Marshall.

"By using existing hardware and technology, we aim to create a multipurpose vehicle that can demonstrate the capabilities of this flexible system on early mission objectives."

NASA's baseline plan is to use an ICPS for SLS on the uncrewed Exploration Mission-1, with an option for a second ICPS that may be used for a crewed Exploration Mission-2.

NASA continues to examine its timeline for integrating an upper stage and evolving SLS towards a 130-metric-ton (143 ton) version that will send humans to Mars.

NASA recently signed a contract agreement with Boeing for the ICPS, completing all definitisation contracts for the major SLS elements.

The interim cryogenic propulsion stage is managed under the SLS Program by the Spacecraft and Payload Integration and Evolution Office at Marshall.

The first flight test of the SLS will feature a configuration for a 70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit to test the performance of the integrated system.

As the SLS evolves, it will provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions even farther into our solar system.

Large, Fast and Rare Meteorite hits the Earth

Geology professor Qing-zhu Yin holds a fragment of the Sutter Mill meteorite that exploded over the Sierra foothills this past spring. (Gregory Urquiaga/UC Davis photo).

A meteorite that exploded as a fireball over California's Sierra foothills this past spring was among the fastest, rarest meteorites known to have hit the Earth, and it traveled a highly eccentric orbital route to get here.

An international team of scientists presents these and other findings in a study published Friday, Dec. 21, in the journal Science.

The 70-member team included nine researchers from UC Davis, along with scientists from the SETI Institute, NASA and other institutions.

The researchers found that the meteorite that fell over Northern California on April 22 was the rarest type known to have hit the Earth - a carbonaceous chondrite. It is composed of cosmic dust and presolar materials that helped form the planets of the solar system.

The scientists learned that the meteorite formed about 4.5 billion years ago was knocked off its parent body, which may have been an asteroid or a Jupiter-family comet, roughly 50,000 years ago.

Once it left the comet, it began its journey to Earth and exploded over Sutter's Mill, the gold discovery site that sparked the California Gold Rush.

As it flew toward Earth, it traveled an eccentric course through the solar system, flying from an orbit close to Jupiter toward the sun, passing by Mercury and Venus, and then flying out to hit Earth.

The high-speed, minivan-sized meteorite entered the atmosphere at about 64,000 miles per hour.

The study said it was the fastest, "most energetic" reported meteorite that's fallen since 2008, when an asteroid fell over Sudan.

"If this were a much bigger object and had landed in a more populated area, then this could have been a disaster," said co-author and UC Davis geology professor Qing-zhu Yin. "But, in this case, it is a happy."

Before entering Earth's atmosphere, the meteorite is estimated to have weighed roughly 100,000 pounds but most of that mass burned away when the meteorite exploded. Scientists and private collectors have recovered about 2 pounds remaining.